Deployable Collapsible Engineered Material Systems For Runway Safety

ABSTRACT

A collapsible material system for slowing a vehicle. The system including: a predetermined thickness of collapsible material disposed over a base; a covering disposed over a top surface of the collapsible material over which the vehicle travels; and a transition portion that further includes: a predetermined thickness of collapsible transition material disposed over a base; and a transition covering disposed over a top surface of the collapsible material over which the vehicle travels. Where one of the collapsible transition material and the transition covering have a different characteristic from the collapsible material and the covering, respectively.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Divisional Application of U.S. application Ser.No. 11/980,285, filed on Oct. 30, 2007, the entire contents of which isincorporated herein by its reference.

BACKGROUND

1. Field of the Invention

The present invention relates generally to emergency apparatus for usewith aircraft runways, and more particularly, to collapsible concretesystems for runways.

2. Prior Art

Runway segments are sometimes added to the end of runways that areconstructed with a special type of “concrete” that collapses in a moreor less controlled manner under the load of an airplane tire, generallyreferred to as Engineered Material Arresting System (EMAS). Such runwaysegments have the problem of lack of control because the collapsed EMAStends to constrain the tire to travel, more or less, in the generated“groove”, making it difficult for the plane to maneuver (turn) sidewaysdue to the resistance that the uncrushed “EMAS wall” provides againstthe tire as it attempts to turn sideways.

In addition, the EMAS material cannot be formed such that it issufficiently homogeneous to prevent bumpy rides.

In addition, the collapsible EMAS runway breaks up into smaller piecesthat can be projected out towards the aircraft, thus creating a safetyhazard.

In addition, the collapsible EMAS runway cannot support the weight ofthe vehicle that is intended to use it in emergency situation. As aresult, the collapsible EMAS runway sections cannot be used for regularlanding and take-off of aircraft.

In addition, once used by an aircraft to slow its speed and bring it toa stop, the collapsible EMAS runway section becomes essentiallyunusable. As a result, the related runway may have to be closed for arelatively long periods to allow the repair crew to repair the damagedsection of the collapsible EMAS runway section.

SUMMARY

Therefore, there exists a need in the art to overcome the deficienciesof the collapsible EMAS systems of the prior art.

Accordingly, a collapsible material system for slowing a vehicle isprovided. The system comprising: a predetermined thickness ofcollapsible material disposed over a base; a plurality of panelsdisposed over a top surface of the collapsible material over which thevehicle travels; and a support structure for supporting one or more ofthe plurality of panels in a first position and for allowing thecollapsible material to be compressed under the weight of the vehicle ina second position.

The collapsible material system can further comprise a hinge disposedbetween adjacent panels of the plurality of panels. The hinge can bedisposed to pivot about an axis parallel to a direction of travel of thevehicle. The hinge can be disposed to pivot about an axis perpendicularto a direction of travel of the vehicle. The hinge can further comprisesa seal.

The collapsible material system can further comprise a seal disposedbetween adjacent panels of the plurality of panels.

The collapsible material system can further comprise a transitionportion comprising: a predetermined thickness of collapsible transitionmaterial disposed over a base; one or more transition panels disposedover a top surface of the collapsible material over which the vehicletravels; and a transition support structure for supporting the one ormore panels in a first position and for allowing the collapsiblematerial to be compressed under the weight of the vehicle in a secondposition; wherein one of the collapsible transition material and the oneor more transition panels have a different characteristic from thecollapsible material and the plurality of panels, respectively. Thedifferent characteristic can be a different orientation of the one ormore transition panels. The different characteristic can be a differentresistance to compression of the transition material.

The support structure can comprise: a linkage having two or more links,one of the two or more links being connected to the base and the otherof the two or more links being connected one or more of the plurality ofpanels; and one or more locking elements for selectively locking andunlocking the linkage between a locked state corresponding to the firstposition and an unlocked state corresponding to the second position.

The support structure can comprise: a tubular member connected to one ofthe base and one or more of the plurality of panels; and one or moremembers slidingly disposed with the tubular member connected to theother of the base and one or more of the plurality of panels; whereinthe one or more member are actuatable between a locked statecorresponding to the first position and an unlocked state correspondingto the second position.

Also provided is a collapsible material system for slowing a vehicle.The system comprising: a predetermined thickness of collapsible materialdisposed over a base; a covering disposed over a top surface of thecollapsible material over which the vehicle travels; and a transitionportion comprising: a predetermined thickness of collapsible transitionmaterial disposed over a base; and a transition covering disposed over atop surface of the collapsible material over which the vehicle travels;and wherein one of the collapsible transition material and thetransition covering have a different characteristic from the collapsiblematerial and the covering, respectively.

The different characteristic can be a different orientation of thetransition covering. The different characteristic can be a differentresistance to compression of the transition material.

Still further provided is a method for slowing a vehicle. The methodcomprising: disposing a predetermined thickness of collapsible materialover a base; disposing a plurality of panels over a top surface of thecollapsible material over which the vehicle travels; and selectivelyeither supporting one or more of the plurality of panels or allowing thecollapsible material to be compressed under the weight of the vehicle.

The method can further comprise pivoting adjacent panels of theplurality of panels with respect to each other.

The method can further comprise sealing between adjacent panels of theplurality of panels.

The method can further comprise: providing a transition portioncomprising: a predetermined thickness of collapsible transition materialdisposed over a base; one or more transition panels disposed over a topsurface of the collapsible material over which the vehicle travels; anda transition support structure for supporting the one or more panels ina first position and for allowing the collapsible material to becompressed under the weight of the vehicle in a second position; andproviding one of the collapsible transition material and the one or moretransition panels have a different characteristic from the collapsiblematerial and the plurality of panels, respectively.

The providing of the one of the collapsible transition material and theone or more transition panels to have a different characteristic fromthe collapsible material and the plurality of panels can comprisesdiffering an orientation of the one or more transition panels.

The providing of the one of the collapsible transition material and theone or more transition panels to have a different characteristic fromthe collapsible material and the plurality of panels can comprisesdiffering a resistance to compression of the transition material.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the apparatus andmethods of the present invention will become better understood withregard to the following description, appended claims, and accompanyingdrawings where:

FIG. 1 illustrates an embodiment of a deployable collapsible EMASmaterials based system having substantially rigid structures deployed.

FIG. 2 illustrates the deployable collapsible EMAS materials basedsystem of FIG. 1 in which a wheeled vehicle travels over the same.

FIG. 3 illustrates the deployable collapsible EMAS materials basedsystem of FIG. 1 with the substantially rigid structures in a retracted(un-deployed state).

FIG. 4 illustrates the deployable collapsible EMAS materials basedsystem of FIG. 3 where a wheeled vehicle has collapsed a portionthereof.

FIG. 5 illustrates a variation of the deployable collapsible EMASmaterials based system of FIG. 4 having a transition region.

FIG. 6 illustrates another embodiment of a deployable collapsible EMASmaterials based system with the substantially rigid structures in aretracted (un-deployed state).

FIG. 7 illustrates the deployable collapsible EMAS materials basedsystem of FIG. 7 having a transition region.

FIG. 8 illustrates an embodiment of a substantially rigid structure.

FIG. 9 illustrates another embodiment of a substantially rigidstructure.

FIG. 10 illustrates yet another embodiment of a substantially rigidstructure.

FIG. 11 illustrates a top view of another embodiment of a deployablecollapsible EMAS materials based system.

DETAILED DESCRIPTION

Although this invention is applicable to numerous and various types ofroadways and surfaces, it has been found particularly useful in theenvironment of runways for aircraft. Therefore, without limiting theapplicability of the invention to runways for aircraft, the inventionwill be described in such environment. Those skilled in the art willappreciate that the collapsible EMAS materials based systems of thepresent invention can be used on roadways for automobiles and trucks andfor other wheeled vehicles.

Referring now to FIG. 1, there is shown a first embodiment of adeployable collapsible EMAS materials based (hereinafter referred to ascollapsible material based) system, generally referred to by referencenumeral 100. The collapsible material based system 100 has apredetermined thickness t of collapsible material 102 over a base 104.The fabrication of collapsible material and the proper thickness for thesame for different applications is well known in the art. Generally, thecollapsible material can be provided in blocks and stacked along thebase 104 to cover an appropriate portion of the base. The collapsiblematerial system 102 further has relatively rigid panels 105, which canbe separate from each other or preferably interconnected, such as by ahinge 106 to allow relative rotation about axes lateral to the directionof travel 107.

The hinges 106 that connect the panels 105 may be constructed as anarrow “strip” of relatively flexible material (not shown) to join thepanels as well as seal the collapsible material 102 and protect it fromelements such as rain, snow, etc., and essentially act as living joints.Alternatively, even when mechanical hinges 106 are used, the panels maystill be joined together on the top surface with similar narrow strip ofrelatively flexible material to protect the underlying collapsiblematerial 102. The provision of such narrow strip of relatively flexiblematerial would have the added advantage of providing the collapsiblematerials based system 100 with a smooth surface.

The panels 105 are supported by substantially rigid structures 108, suchthat under the load transmitted by the wheel 110 of a typical vehicle111 that will use the system 100, as shown in FIG. 2, it would not causethe collapsible material system 102 to be crushed.

The support structures 108 are, however, deployable, i.e., in itsdeployed state they are substantially rigid structures and would supportthe load exerted by the wheel 110 of the passing vehicle 111 over thesupported panels 105. In their un-deployed (retracted) state 113, thesupports provide minimal to no resistance to the load exerted by thewheel 110 of the passing vehicle 111 over the “un-supported” panels 105,thereby allowing the said load to press the panels 105 against thecollapsible material system 102, FIG. 3. This would then cause thecollapsible materials 102 to be crushed as shown in FIG. 4 to certaindepth 115 (the fully crushed region is indicated as 114) depending onthe load exerted by the wheel 110 of the passing vehicle 111, therebyabsorbing the kinetic energy of the passing vehicle and eventuallybringing it to a stop or slowing it down as intended by the system userand/or designer. Hereinafter, the aforementioned support structures 108are referred to as “deployable support structures”.

The different methods of providing the aforementioned deployable supportstructures and their various embodiments are described below.

The length (L), FIG. 1, of the panels 105 is chosen depending on thesize of the typical wheel that will use the system (or a range of wheelsizes). The width of the panels 105 (perpendicular to the direction oftravel 107) can vary from the width of the typical wheel that will usethe system (and perhaps even smaller) to the width of the runway,however, in general, the larger the surface area of the panel 105, theless crushing force is exerted on the collapsible material covered bythe panel 105.

The hinges 106 may be provided with certain amount of flexibility and/orplay to allow certain amount of relative displacement between the panels105 in the vertical plane of the schematic cross-sections of FIGS. 1-2.Such relative displacements would accommodate certain amount of rotationand downward motion of one panel 105 relative to the next panel as atypical wheel 110 rolls over panels 105 as shown in FIG. 3. Thus, thehinges 106 would allow the panels 105 to assume a sloped configurationas the vehicle 111 wheel 110 rolls over a panel and to push the leadingedge 112 down as shown in FIG. 3.

In general, the side by side panels 105, i.e., the panels positionedside by side in the direction perpendicular to the direction of thetravel 107 of the vehicle 111 are preferably connected by flexibleelements (not shown) so that the depression of one panel 105 under theweight of the vehicle 111 transmitted by the wheel 110 to the said panelwould also exert a force on the sides of the adjacent panels to avoidthe creation of abrupt discontinuities.

In the FIGS. 1-4, all the like features are denoted by identicalreference numerals.

To make the transition from the regular section of a runway 119 commonlyconstructed with concrete 117, FIG. 5, to the deployable collapsiblematerials based system section 100, a slightly sloped transition section118 is constructed with similar panels 105 that are hinged together withsimilar hinges 106, and supported by appropriately sized supportstructures 108. Similar collapsible material 102 that are appropriatelysized 116 are similarly used to fill the space between the panels 105 ofthe transition section 118 and the base 104 as shown in FIG. 5. Thetransition section 118 would allow the vehicle 111 to begin todecelerate slowly and smoothly to its final deceleration rate as thewheel 110 of the vehicle 111 travels from the regular section of therunway 119 over to the transition section 118 and from there to thedeployable collapsible materials based system section 100.

The resulting runway section having the collapsible concrete system 100will then act very similar to the runway system described in U.S. Pat.No. 6,969,213 entitled “Roadway for Decelerating a vehicle Including anAircraft,” the entire contents of which is incorporated herein byreference. In the present collapsible concrete system, 100, thecollapsible concrete 102 and 116 (FIGS. 1-5) is used in place of thesupport and control elements disclosed in U.S. Pat. No. 6,969,213. Thedifference is that when substantially rigid support structures 108(FIGS. 1, 2 and 5) are in their retracted state 113 (FIGS. 3-4), thekinetic energy of the vehicle is used to crush the collapsible concrete(collapsible EMAS materials) rather than being stored in springs orabsorbed by dampers or brake elements. Thus, as shown in FIG. 5, as awheel 110 of the vehicle 111 enters the collapsible EMAS materialssystem 100, the wheel 110 first enters the transition section 118 fromthe regular runway section 119 as shown in FIG. 5. The load transmittedby the wheel 110 will then begin to press the panels 105 of thetransition section 118, forcing the panels to crush the collapsiblematerials 116 under the transition section 118. The wheel will thenreach the level section of the collapsible EMAS materials system 100,and keep on depressing the panels 105 down and crush the collapsiblematerials 102 to certain height 115, FIG. 4, which is dependent on thelevel of load transmitted by the wheel 110 of the vehicle 111.

In addition to the panels 105 preventing debris from being thrown,another advantage of using such panels 105 over collapsible EMASmaterials 102 (116) is that the vehicle travels much smoother since itwould average out the strength of the collapsible EMAS materials system102 (116), the homogeneity of which is hard to control.

Still another advantage of the collapsible EMAS materials system 100 isthat there is no resulting loss of control of the vehicle 111 as ittravels over the panels 105 rather than in grooves generated by thesinking wheel 110 in the collapsible EMAS materials 102 (116) in theabsence of the panels 105.

Still another advantage of the collapsible materials system 100 is thatwith the substantially rigid support structures 108 deployed (FIGS. 1, 2and 5), the system 100 is substantially rigid and the load transmittedby the wheel 110 of the vehicle 111 will be carried substantially by thesubstantially rigid support structure 108. The section 100 wouldtherefore function as a regular section of a runway and add to the totallength of the regular runway, a feature which is highly desirable forall runways. However, when an emergency situation is encountered, thesubstantially rigid support structures 108 are retracted to theirun-deployed (retracted) state, FIGS. 2-3, and the vehicle 110 travelingin the direction 107 is decelerated safely to a stop.

Still another advantage of the collapsible EMAS materials system 100 isthat following an emergency use of the section of the runway todecelerate a vehicle, for example a runaway aircraft, the substantiallyrigid support structures 108 may again be deployed and the section ofthe runway used for ordinary landing while the damaged collapsible EMASmaterials (102 and 116, FIG. 5) sections are ready to be replaced. As aresult, the runway does not have to be closed while the collapsible EMASmaterials (102 and 116, FIG. 5) sections are being made. In addition,the collapsible EMAS materials system 100 is still mostly effectivesince the chances of a second runaway vehicle to follow exactly the pathof a previous runaway vehicle is very small.

In another embodiment, the schematics of which is shown in FIG. 6, acollapsible materials based system 120 is constructed such that thepanels 121 connected together with hinges 132 are flush with the regularrunway section 122, both for the transition section 123 panels and themain section 124 panels. In their deployed state, the aforementionedsubstantially rigid support structures 133 support the panels 121, suchthat under the load transmitted by the wheel 125 of a typical vehicle126 that will use the system 120, as shown in FIG. 6, it would not causethe collapsible materials 128 and 130 to be crushed. The collapsibleEMAS materials 128 and 130 of both sections 123 and 123 and thesubstantially rigid support structures 133 are supported by a similarbase (foundation) structure 134.

However, the transition from the regular runway section 122 to thecollapsible materials based system 120 is highly desirable to be smoothfor the wheel 125 of the vehicle 126, i.e., the wheel 125 of the vehicle126 is desired to slowly increase its vertical (downward) travel (i.e.,crushing depth of 127 of the collapsible EMAS materials 128) as it movesfrom the regular runway section 122 to over the panels 121 to itsnominal depth 129, FIG. 7. To this end, the collapsible EMAS materials128 following the regular runway section 122 in the transition section123 is made out of stronger collapsible EMAS materials, i.e.,collapsible EMAS materials that crush less under the same load, and thenbecome progressively weaker to the nominal strength of the collapsibleEMAS materials 130 of the remaining section 124 of the collapsible EMASmaterials system 120. As a result, as the wheel 125 of the vehicle 126traveling in the direction 131 enters the section of the runwayconstructed with the collapsible materials based system 120, the firstfew panels 121 positioned along the aforementioned transition section123 are depressed due to the crushing of the stronger collapsible EMASmaterials 128 continuously more to bring the wheel 125 smoothly to itsnominal depth 129 over the remaining section 124 of the collapsiblematerials system 120 as shown in FIG. 7.

The support structures (108 in FIGS. 1-2 and 5 and 133 in FIGS. 6-7),while supporting the vehicle load over the substantially rigid panels(105 in FIGS. 1-5 and 121 in FIGS. 6 and 7), are constructed to preventthe collapsible materials (102 in FIGS. 1-5 and 128 and 130 in FIGS. 6and 7) from being crushed under the weight of the vehicle (111 in FIGS.2-5 and 126 in FIGS. 6 and 7) as transmitted by the vehicle tires (110in FIGS. 2-5 and 125 in FIGS. 6 and 7). The support structures 108 and133, however, are capable of being released, i.e., being made incapableof supporting the aforementioned vehicle load, thereby allowing crushingof the collapsible materials (102, 128 and 130) under the vehicle load.

The support structure releasing action may be initiated manually, forexample by the flight control personnel or by the aircraft crew, or maybe initiated automatically when sensors measuring the speed of thelanding aircraft determine that the aircraft is moving too fast and mayrun past the runway. The automatic means of release mechanism initiationmay also be onboard the aircraft and initiate the release directly or bycommunicating with a runway station. The support structures 108 and 133and their release mechanisms may be constructed in a varieties of ways,some of which are described in the following embodiments.

In general, the mechanisms for the support structures 108 and 133 can beconfigured to either retract out of the direction of collapsiblematerial (102, 128 and 130) crushing, or can be configured to move withthe panels (105 and 121) with minimal resistance. Alternatively, whilemoving with the panels 105 and 121, the support structures may alsoprovide certain amount of (braking-like) resistance, thereby absorbing aportion of the kinetic energy of the vehicle.

In one embodiment, the support structures 108 and 133 are designed aslinkage mechanisms with a releasable locking element, which when locked,would transform the mechanism to a (substantially rigid) structure (nodegree-of-freedom for motion), supporting the vehicle load on the panels105 and 121 as previously described. However, once the locking mechanismis released, the linkage mechanism is essentially free to “collapse”,thereby allowing the panels 105 and 121 to crush the underlyingcollapsible materials (102, 128 and 130).

In one embodiment, the linkage mechanism types used for the constructionof the present support structures 108 and/or 133 have at least twodegrees-of-freedom in motion to allow arbitrary motion of the panels 105and 121 relative to the base foundation (104 in FIGS. 1-5 and 134 inFIGS. 6-7). In general, fewer degrees-of-freedom in motion is preferablesince it would require fewer locking elements to transform the mechanisminto a substantially rigid structure (in general, one such lockingmechanism is required for each degree-of-freedom of the linkagemechanism to transform the mechanism into a substantially rigidstructure).

One such degree-of-freedom linkage mechanism embodiment for theconstruction of the present support structures 108 and/or 133 is shownin the schematic drawing of FIG. 8. This mechanism is constructed withtwo links 142 and 143, which are connected together with a hinge 146.The link 142 is hinged to the panel 141 through the attachment support144. The link 143 is in turn attached to the runway foundation 151through the support 145. The panels 141 are shown to be attached to eachother by hinges 140. The locking elements 147 and 149 are provided toprevent rotary motion of the links 143 and 142, respectively, relativeto the runway foundation, portions of which are shown as 148. It isnoted that in the schematic of FIG. 8 and for the sake of simplicity thelocking elements 147 and 149 are shown only on one side the links 143and 142, but in an actual device the locking elements are intended toprovide locking elements positioned on both sides of the links (e.g., byproviding U shaped elements instead of blocks 147 and 149 as shown inFIG. 8) to restrict the links 143 and 142 from undergoing any rotationalmotions. When the locking elements 147 and 149 are preventing the links143 and 142 from rotating, the two links function as a structure, i.e.,function as substantially rigid support structures 108 and 133, therebysupporting the load 150 exerted by the vehicle wheel (110 and 125 inFIGS. 1-7) on the panels 141, thereby preventing the panel to be pusheddown and crush the collapsible materials 102 or 128 and/or 130 (notshown in FIG. 8). When a vehicle traveling over the runway section needsto be slowed down, the locking elements 147 and 149 are withdrawn,thereby preventing the links 143 and 142 (the linkage mechanism) toprovide a substantial resistance to the applied load 150, therebyallowing the panels 141 to crush the collapsible materials 102 or 128and/or 130, absorbing part of the kinetic energy of the vehicle andtherefore slowing the vehicle down.

The links 149 and 147 (linkage mechanism) may be provided with springelements (not shown) to bias them into their collapsed position. Thelinkage mechanism may also be provided with braking elements (frictionalor viscous damping type) to absorb parts of the kinetic energy of thepassing vehicle as the weight of vehicle pushes the panels 141 down tocrush the collapsible materials 102 or 128 and/or 130.

In another embodiment of the present invention, the linkage mechanismtype used for the construction of the present support structures 108and/or 133 has only one degrees-of-freedom in motion; thereby would onlyallow the panels 105 and 121 to undergo a prescribed motion relative tothe runway foundation (104 and 134). The prescribed motion is preferablythe actual motion pattern of the panels 105 and 121 as the vehicle loadis applied to the surface of the panels and travel along its length,causing the collapsible materials 102 or 128 and/or 130 to crush.However, since this pattern of motion for the panels 105 and 121 isdifferent for different vehicles and their speed, one compromise wouldbe to provide linkage mechanisms that allow only vertical motion, andattach them to the panels by a, preferably, spherical joint that wouldallow for rotational motion of the panels 105 and 121 about axesparallel to the plane of the foundation, i.e., usually the horizontalplane. The rotation of the panels 105 and 121 about the vertical axis isprevented since more than one support structure 108 and/or 133 is usedfor each said panels.

One such an embodiment is designed as a “scissor” type of linkagemechanism 160 shown in the schematic drawing of FIG. 9. The scissormechanism is constructed with a series of pairs of links 171 that arejoined together as shown in FIG. 9 with hinges 172. On the foundation170 side, one of the links 171 is hinged to the support 165, which is inturn fixed to the foundation 170. The other link 171 of the scissormechanism 160 is hinged to the support 166. The support 166 rests overthe surface of the foundation 170 and is free to translate along theline connecting the supports 165 and 166. Similarly on the panel 161side, one of the links 171 is hinged to the support 164, which is fixedto the plate 173. The other link 171 is then hinged to the support 175,which is free to translate along the line connecting the supports 164and 175. The panel 161 is then supported by the scissor type mechanismvia the ball joint 174. The panels 161 are attached together aspreviously described by the hinge joints 162. The ball joint 174 may bea living joint.

In the schematic drawing of FIG. 9, the translation of the support 166over the surface of the foundation 170 away from the fixed support 165is prevented by the locking element 168 which is positioned between thesupport 166 and the stop 167, which is fixed to the foundation 170. Whenthe locking element 168 is positioned as shown in FIG. 9 between thesupport 166 and the stop 167, then the scissor mechanism 160 issubstantially rigid and the top plate 173 can support the vehicle load169 that is applied to the panel 161 as the vehicle travels over thesaid panel. However, when the locking element 168 is pulled away fromits aforementioned locking position shown in FIG. 1, then the support166 is free to translate away from the fixed support 165, therebyallowing the scissor mechanism to collapse, thereby allowing the panel161 to crush the collapsible materials 102 or 128 and/or 130 as thevehicle travels over the panel 161 and applies the load 169 to the saidpanel.

As described for the mechanism of FIG. 8, the links 171 (linkagemechanism) may be provided with spring elements (not shown) to bias theminto their collapsed position. The linkage mechanism may also beprovided with braking elements (frictional or viscous damping type) toabsorb a portion of the kinetic energy of the passing vehicle as theweight of the vehicle pushes the panels 161 down to crush thecollapsible materials 102 or 128 and/or 130 (not shown).

In yet another embodiment, the support structures 108 and/or 133 isconstructed as a one degree-of-freedom telescopic column type ofmechanism 180 shown in the schematic drawing of FIG. 10. Here, themechanism 180 is shown to consist of a moving section 185 (can becylindrical or other shapes), which could travel down inside the secondtubular section 186. The section 186 is fixed to the foundation 183, andis preferably buried substantially inside the foundation for increasedsupport and to allow the section 185 to move down a sufficient amountfor the proper operation of the present system. The locking element 188provides the means to lock the section 185 of the telescopic mechanism180 up in the position shown in FIG. 10. In this position, thetelescopic mechanism functions as a support structure support structures108 and/or 133, and support the load 184 applied by the tire of thevehicle passing over the panel 181 via the ball joint 187. The panels181 are attached together as previously described by the hinge joints182. The ball joint 187 may be a living joint.

When the locking element 187 is pulled out of the telescopic (column)mechanism 180, the section 185 is free to retract into the section 186,thereby allowing the panel 181 to crush the collapsible materials 102 or128 and/or 130 (not shown) as the vehicle travels over the panel 181 andapplies the load 184 to the said panel.

As described for the mechanisms of FIGS. 8 and 9, spring elements (notshown) may be used to bias the translation of the section 185 inside thesection 186 of the telescopic mechanism 180 to bias the mechanism intoits collapsed position. The telescopic mechanism may also be providedwith braking elements (frictional or viscous damping type) to absorbparts of the kinetic energy of the passing vehicle as the weight ofvehicle pushes the panels 181 down to crush the collapsible materials102 or 128 and/or 130 (not shown).

Such telescopic column type mechanisms may also be constructed with morethan one telescopic section to minimize the length of the buried section186. However, since each section has to be provided with a separatelocking element 188, the resulting support structure will have morecomponents and more locking elements to be removed when the runwaysection is intended to be used to slow the passing vehicle.

Referring now to FIG. 1, there is shown a top view of another embodimentof a collapsible material based system 200. In the embodiment of FIG.11, in addition to the panels 105 being pivotal about hinges (orflexures) 106 which pivot about an axis perpendicular to the directionof travel 107, the panels 105 can also be pivotal about hinges (orflexures 202) which pivot about an axis parallel to the direction oftravel so as to arrest any component of motion of the aircraft in thesideways direction which would otherwise cause the aircraft to leave theside of the runway. In such an embodiment, an appropriate number ofsupport structures 108 are needed to support each panel 105, such asthree or more of such support structures 108 per panel 105. Theside-to-side (perpendicular to the direction of travel 107) spacing ofthe hinges 202 can be more, less or the same as the lengthwise spacingbetween hinges 106. However, it is preferred that the side-to-sidespacing between hinges 202 is greater than the lengthwise spacingbetween hinges 106 such that the panels are wider in the side-to-sidedirection than they are in the lengthwise (direction of travel 107)direction.

While there has been shown and described what is considered to bepreferred embodiments of the invention, it will, of course, beunderstood that various modifications and changes in form or detailcould readily be made without departing from the spirit of theinvention. It is therefore intended that the invention be not limited tothe exact forms described and illustrated, but should be constructed tocover all modifications that may fall within the scope of the appendedclaims.

What is claimed is:
 1. A collapsible material system for slowing avehicle, the system comprising: a predetermined thickness of collapsiblematerial disposed over a base; a covering disposed over a top surface ofthe collapsible material over which the vehicle travels; and atransition portion comprising: a predetermined thickness of collapsibletransition material disposed over a base; and a transition coveringdisposed over a top surface of the collapsible material over which thevehicle travels; and wherein one of the collapsible transition materialand the transition covering have a different characteristic from thecollapsible material and the covering, respectively.
 2. The collapsiblematerial system of claim 1, wherein the different characteristic is adifferent orientation of the transition covering.
 3. The collapsiblematerial system of claim 1, wherein the different characteristic is adifferent resistance to compression of the transition material.